Whenever I got a PM, I would get "notified", and a pop-up notification that I had a PM waiting would appear when I got onto FSN.
Not anymore.

I really can't say if it's some 'glitch' with the board software, or if it has something to do with Windows 7.
I don't get that many PMs, but when I really noticed it was after I stopped using my XP Pro laptop, and started using my Windows 7 laptop, sometime in Sept.

ETA: I went and checked my preferences again. I know that in the past, both of the choices (below) were marked "Yes". But when I just double-checked a few minutes ago, I noticed that "Pop up window on new private message" was marked "No". I changed it back to "Yes".